Electrodiagnostic Testing for Carpal Tunnel Syndrome When Routine Median Sensory and Thenar Motor Responses Are Absent

PURPOSE

The cardinal symptoms of carpal tunnel syndrome (CTS) include pain in the affected hand(s). The median/second lumbrical nerve (Med2ndL) seems relatively preserved in severe CTS, with previous small studies suggesting its value in electromyogram to localize a median neuropathy to the wrist when both initial routine sensory and thenar motor responses are absent.

METHODS

This is a retrospective analysis of 208 hands in 183 patients with electrophysiologically markedly severe CTS (absent routine sensory and thenar motor median responses) who underwent stimulation of both the Med2ndL and ulnar/second dorsal interosseous (Uln2ndDIn) motor nerves. A Med2ndL distal latency of ≥ 0.5 milliseconds when compared with the Uln2ndDIn supported the diagnosis of CTS. The presence or absence of hand pain was recorded if these data were available.

RESULTS

Some 83.7% of hands (172/208) in 183 patients with markedly severe CTS had preservation of the Med2ndL meeting criteria for CTS. In those with pain data available, 77.1% (81/105) of hands had no pain. Of those 105 hands, 87 had preservation of the Med2ndL with 79.3% (69/87) demonstrating no pain.

CONCLUSIONS

This is a large study that demonstrates the relative preservation of the Med2ndL response in markedly severe CTS. Assessment of the Med2ndL should be considered to electrophysiologically support CTS when routine sensory and thenar motor responses are absent. In addition, most patients with electrophysiologically markedly severe CTS had no pain.

Biomarkers of Recent Cannabis Use in Blood, Oral Fluid and Breath

Proving driving under the influence of cannabis (DUIC) is difficult. Establishing a biomarker of recent use to supplement behavioral observations may be a useful alternative strategy. We determined whether cannabinoid concentrations in blood, oral fluid (OF), or breath could identify use within 3h, likely the period of greatest impairment. In a randomized trial, 191 frequent (≥4/week) and occasional (<4/week) cannabis users smoked one cannabis (placebo [0.02%], 5.9% or 13.4% THC) cigarette ad libitum. Blood, OF and breath samples were collected prior to and up to 6h after smoking. Samples were analyzed for 10 cannabinoids in OF, 8 in blood, and THC in breath. Frequent users had more residual THC in blood and were categorized as "recently used" prior to smoking; this did not occur in OF. Per se limits ranging from undetectable to 5 ng/mL THC in blood offered limited usefulness as biomarkers of recent use. Cannabinol (CBN, cutoff=1 ng/mL) in blood offered 100% specificity but only 31.4% sensitivity, resulting in 100% PPV and 94.0% NPV at 4.3% prevalence; but CBN may vary by cannabis chemovar. A 10 ng/mL THC cutoff in OF exhibited the overall highest performance to detect use within 3h (99.7% specificity, 82.4% sensitivity, 92.5% PPV, 99.2% NPV) but was still detectable in 23.2% of participants ~4.4h post smoking limiting specificity at later time points. OF THC may be a helpful indicator of recent cannabis intake, but this does not equate to impairment. Behavioral assessment of impairment is still required to determine DUIC. This study only involved cannabis inhalation and additional research evaluating alternative routes of ingestion (i.e., oral) is needed.

Quantitative Electromyography

The discipline of electromyography (EMG) relies on the skillful application of a wide range of techniques, skills, and intuitions—all of which derive from practiced analysis of electrical signals recorded from muscle. A proper understanding of the available equipment as well as the current strategies to classify motor unit potentials (MUPs) and the muscles from which they are recorded as normal, neurogenic, or myopathic underlies EMG practice. This chapter reviews EMG electrodes, MUP characteristics, and a range of quantitative methods to characterize both MUPs and muscles to determine whether the muscle in question is normal or not in order to help the electromyographer achieve an accurate EMG interpretation.

AANEM - IFCN glossary of terms in neuromuscular electrodiagnostic medicine and ultrasound

Modern neuromuscular electrodiagnosis (EDX) and neuromuscular ultrasound (NMUS) require a universal language for effective communication in clinical practice and research and, in particular, for teaching young colleagues. Therefore, the AANEM and the IFCN have decided to publish a joint glossary as they feel the need for an updated terminology to support educational activities in neuromuscular EDX and NMUS in all parts of the world. In addition NMUS has been rapidly progressing over the last years and is now widely used in the diagnosis of disorders of nerve and muscle in conjunction with EDX. This glossary has been developed by experts in the field of neuromuscular EDX and NMUS on behalf of the AANEM and the IFCN and has been agreed upon by electronic communication between January and November 2019. It is based on the glossaries of the AANEM from 2015 and of the IFCN from 1999. The EDX and NMUS terms and the explanatory illustrations have been updated and supplemented where necessary. The result is a comprehensive glossary of terms covering all fields of neuromuscular EDX and NMUS. It serves as a standard reference for clinical practice, education and research worldwide.

Novel biallelic variants in MSTO1 associated with mitochondrial myopathy

Mitochondrial disorders are caused by nuclear and mitochondrial pathogenic variants leading to defects in mitochondrial function and cellular respiration. Recently, the nuclear-encoded mitochondrial fusion gene MSTO1 (Misato 1) has been implicated in mitochondrial myopathy and ataxia. Here we report on a 30-yr-old man presenting with a maternally inherited NM_018116.3:c.651C>G, p.F217L missense variant as well as a paternally inherited arr[GRCh37] 1q22(155581773_155706887) × 1 deletion encompassing exons 7-14 of MSTO1 His phenotype included muscle weakness, hypotonia, early motor developmental delay, pectus excavatum, and scoliosis. Testing revealed elevated plasma creatine kinase, and electromyogram results were consistent with longstanding generalized myopathy. These phenotypic features overlap well with previously reported patients harboring biallelic MSTO1 variants. Additionally, our patient presents with dysphagia and restrictive lung disease, not previously reported for MSTO1-associated disorders. The majority of patients with disease-associated variants in MSTO1 present with biallelic variants suggesting autosomal recessive inheritance; however, one family has been reported with a single variant and presumed autosomal dominant inheritance. The pattern of inheritance we observed is consistent with the majority of previous reports suggesting an autosomal recessive disorder. We add to our knowledge of the syndrome caused by variants in MSTO1 and provide additional evidence supporting autosomal recessive inheritance. We also describe phenotypic features not reported in previous cases, although further research is needed to confirm they are associated with defects in MSTO1.

A case of YY1-associated syndromic learning disability or Gabriele-de Vries syndrome with myasthenia gravis

Exome sequencing is being used increasingly to evaluate patients with intellectual disability. YY1 is a ubiquitously distributed transcription factor belonging to the GLIKruppel class of zinc finger proteins recently recognized as the causative gene in 23 patients for the Gabriele-de Vries syndrome. We report a new case with similar features and a novel variant in YY1, in a region of the gene, which has not previously been reported. A 25 year old female was referred to clinical genetics with a diagnosis of autoimmune myasthenia gravis, facial dysmorphism and learning disability. Chromosomal microarray and gene panel test for congenital myasthenic syndrome was negative. Whole exome sequencing (WES) revealed a presumed pathogenic de novo novel, heterozygous, truncating variant in the YY1 gene, c.860_864delTTAAAA, p.Ile287Argfs*3. The Ile287 residue is conserved across species and is situated in the transcription repressor domain of the protein. This variant is novel and lies in a domain of the protein where no previously reported variants occur. The phenotypic features of our case closely match those of the reported patients. Autoimmune myasthenia gravis has not been reported in these patients and may constitute an expansion of this phenotypic spectrum or perhaps more likely a second unrelated diagnosis.

Focal and entrapment neuropathies

Of the many patterns of peripheral nerve disorders in diabetes mellitus (DM), isolated clinical involvement of single nerves, though less common than distal symmetric polyneuropathy and perhaps polyradiculoneuropathy, constitute an important collection of characteristic syndromes. These fall into four anatomical regions of the body: cranial, upper limb, truncal, and lower limb territories. Each of these groups of mononeuropathies has its own ensemble of epidemiologic patterns, clinical presentations, laboratory and radiologic findings, differential diagnosis, management principles and prognosis.

A trans-Atlantic examination of haddock Melanogrammus aeglefinus food habits

The food habits of Melanogrammus aeglefinus were explored and contrasted across multiple north-eastern and north-western Atlantic Ocean ecosystems, using databases that span multiple decades. The results show that among all ecosystems, echinoderms are a consistent part of M. aeglefinus diet, but patterns emerge regarding where and when M. aeglefinus primarily eat fishes v. echinoderms. Melanogrammus aeglefinus does not regularly exhibit the increase in piscivory with ontogeny that other gadoids often show, and in several ecosystems there is a lower occurrence of piscivory. There is an apparent inverse relationship between the consumption of fishes and echinoderms in M. aeglefinus over time, where certain years show high levels of one prey item and low levels of the other. This apparent binary choice can be viewed as part of a gradient of prey options, contingent upon a suite of factors external to M. aeglefinus dynamics. The energetic consequences of this prey choice are discussed, noting that in some instances it may not be a choice at all.

Quantitative Electromyography

Semi-quantitative EMG methods are in common use in clinical electromyography laboratories but have a number of drawbacks and limitations, including examiner bias in MUP analysis and challenges distinguishing between MUP categories of normal and neurogenic and normal and myopathic waveforms. An array of formal MUP quantitation methods has been developed in recent decades, which seek to address many of the shortcomings of semiquantitative EMG. The advantages of quantitative EMG (QEMG) include: (1) making measurements of MUP recordings consisting of numerical values derived from precise measurements, (2) generating normative data and allowing comparisons with data from patients with suspected neuromuscular diseases, (3) allowing for reproducible results that can be compared at different times by different examiners and in different labs, and (4) allowing accurate assessment of improvement or deterioration in disease severity over time.

Contact Heat Evoked Potentials

Somatic small-diameter fibers in the Aδ‎ and C classes are difficult to assess objectively. Beyond skin punch biopsy for epidermal nerve fiber density, which examines only a small percentage of the cutaneous nerve fibers, nociceptive evoked potentials provide a number of techniques to study these heat- and pain-mediating neural pathways. Of the available approaches, contact heat evoked potentials (CHEPS) present a number of advantages. Using robust and highly quantified discrete bursts of heat by a thermofoil electrode, safeguarded by layers of redundant internal algorithms to insure stimuli remain within strict tolerances, CHEPS evokes scalp responses typically in the 5–50 μ‎V amplitude range in normal adult subjects from Cz–TE into the eighth decade, which can be readily resolved averaging 10–14 stimuli. Having been used in individuals with a variety of peripheral and central disorders affecting spinothalamic pathways, CHEPS is a promising technique in clinical neurophysiology.

Quantifying alosine prey in the diets of marine piscivores in the Gulf of Maine

The objectives of this work were to quantify the spatial and temporal distribution of the occurrence of anadromous fishes (alewife Alosa pseudoharengus, blueback herring Alosa aestivalis and American shad Alosa sapidissima) in the stomachs of demersal fishes in coastal waters of the north-west Atlantic Ocean. Results show that anadromous fishes were detectable and quantifiable in the diets of common marine piscivores for every season sampled. Even though anadromous fishes were not the most abundant prey, they accounted for c. 5-10% of the diet by mass for several marine piscivores. Statistical comparisons of these data with fish diet data from a broad-scale survey of the north-west Atlantic Ocean indicate that the frequency of this trophic interaction was significantly higher within spatially and temporally focused sampling areas of this study than in the broad-scale survey. Odds ratios of anadromous predation were as much as 460 times higher in the targeted sampling as compared with the broad-scale sampling. Analyses indicate that anadromous prey consumption was more concentrated in the near-coastal waters compared with consumption of a similar, but more widely distributed species, the Atlantic herring Clupea harengus. In the context of ecosystem-based fisheries management, the results suggest that even low-frequency feeding events may be locally important, and should be incorporated into ecosystem models.

Acute hypoxic hypoxia and isocapnic hypoxia effects on oculometric features

INTRODUCTION

Visual performance impairment after hypoxia is well recognized in military and civilian aviation. The aims of this study were: 1) to assess oculometric features such as blink metrics, pupillary dynamics, fixations, and saccades as cognitive indicators of early signs of hypoxia; and 2) to analyze the impact of different hypoxic conditions ["hypoxic hypoxia" (HH) and "isocapnic hypoxia" (IH)] on specified oculometrics during mental workloads.

METHODS

Oculometric data were collected on 25 subjects under 3 conditions: normoxia, HH (8% O2 + balance N2), and IH (7% O2 + 5% CO2 + balance N2). The mental workload task consisted of reading aloud linear arrays of numbers after exposure to gas mixtures.

RESULTS

Blink rates were significantly increased under hypoxic conditions (by +100.7% in HH and by +92.8% in IH compared to normoxia). A faster recovery of blink rate was observed in transitioning from IH (23.6% vs. 76.3%) to normoxia. The percentage change in pupil size fluctuation was increased under HH more than under IH (29% vs. 4.4%). Under HH average fixation time and target area size were significantly higher than under IH. Total saccadic times under hypoxic conditions were significantly increased compared with normoxia.

CONCLUSIONS

These results suggest that oculometric changes are indicators of hypoxia, which can be monitored using compact, portable, noninvasive eye-tracking devices in a cockpit analogous environment to detect hypoxia-induced physiological changes in aircrew. Comparative results between HH and IH support the potential role of carbon dioxide in augmenting cerebral perfusion and hence improved tissue oxygen delivery.

Quality improvement in neurology: Distal symmetric polyneuropathy quality measures

Peripheral neuropathy is a common neurologic disorder, affecting 2% to 8% of the population in population-based studies with confirmation by neurologist examination. These prevalence numbers are remarkably stable across developed countries. In 1999, 8.6% of Medicare beneficiaries had neuropathy as a primary or secondary diagnosis, and the cost of treatment was estimated at $3.5 billion (Consumer Price Index adjusted to 2013 $4.9 billion), which did not include outpatient medications. Peripheral neuropathy has many causes and varies in regard to its clinical manifestations and severity. Distal symmetric polyneuropathy (DSP) is the most common pattern of peripheral neuropathy generally and the most common phenotype of neuropathy due to diabetes. Reported prevalence rates of DSP among diabetic patients range from 15% to 37% across large population-based studies, and the prevalence among those with impaired glucose tolerance has been reported to be 11%. DSP can result in weakness, sensory loss, pain, autonomic dysfunction, gait impairment, falls, disability, and impaired quality of life.

Muscle categorization using PDF estimation and Naive Bayes classification

The structure of motor unit potentials (MUPs) and their times of occurrence provide information about the motor units (MUs) that created them. As such, electromyographic (EMG) data can be used to categorize muscles as normal or suffering from a neuromuscular disease. Using pattern discovery (PD) allows clinicians to understand the rationale underlying a certain muscle characterization; i.e. it is transparent. Discretization is required in PD, which leads to some loss in accuracy. In this work, characterization techniques that are based on estimating probability density functions (PDFs) for each muscle category are implemented. Characterization probabilities of each motor unit potential train (MUPT) are obtained from these PDFs and then Bayes rule is used to aggregate the MUPT characterization probabilities to calculate muscle level probabilities. Even though this technique is not as transparent as PD, its accuracy is higher than the discrete PD. Ultimately, the goal is to use a technique that is based on both PDFs and PD and make it as transparent and as efficient as possible, but first it was necessary to thoroughly assess how accurate a fully continuous approach can be. Using gaussian PDF estimation achieved improvements in muscle categorization accuracy over PD and further improvements resulted from using feature value histograms to choose more representative PDFs; for instance, using log-normal distribution to represent skewed histograms.

Non-invasive method for rapid bedside estimation of inotropy: theory and preliminary clinical validation

BACKGROUND

There are numerous techniques which attempt to quantify inotropy (or myocardial contractility). None has yet found general acceptance in anaesthesia and critical care as a practical method. We report a novel approach to the determination of inotropy as a bedside procedure which could identify low inotropy states in patients with clinical heart failure.

METHODS

We estimated the potential and kinetic energy delivered by the left ventricle using continuous-wave Doppler ultrasound (ultrasonic cardiac output monitor, Uscom, Sydney, Australia) and data available at the point of care. A formula to calculate effective inotropy [Smith-Madigan inotropy index (SMII)] was tested against historical haemodynamic data for 250 control subjects (ASA I patients from preoperative clinic) and 83 patients with acute left ventricular failure (LVF) of New York Heart Association Grade 4 (LVF group). The ratio of potential to kinetic energy (PKR) was investigated as a measure of arterial impedance.

RESULTS

Significant differences were found between the control and LVF groups for cardiac index, mean (range)=3.37 (2.84-5.32) vs 1.84 (1.43-2.26) litre min(-1) m(-2); stroke volume index (SVI), 49.2 (39-55) vs 34.3 (23-37) ml m(-2); systemic vascular resistance, 893 (644-1242) vs 1960 (1744-4048) dyn s cm(-5); SMII, 1.78 (1.35-2.24) vs 0.73 (0.43-0.97) W m(-2); and PKR, 29:1 (24-35:1) vs 124:1 (96-174:1), P<0.001 in each case. Normal ranges were calculated for SMII and PKR as mean (+/-1.96) standard deviations, yielding 1.6-2.2 W m(-2) for SMII, and 25-34:1 for PKR.

CONCLUSION

The method clearly identified the two clinical groups with no overlap of data points. The discriminant power of SMII and PKR may offer valuable diagnostic methods and monitoring tools in anaesthesia and critical care. This is the first report of normal ranges for SMII and PKR.

Surgeon fatigue and postural stability: is robotic better than laparoscopic surgery?

OBJECTIVE

To compare muscular fatigue and postural stability of surgeons before and after laparoscopic and robotic surgery.

SUBJECTS AND METHODS

The design of this study is Class II. A consecutive cohort of patients presenting at an academic tertiary-care center for scheduled gynecologic surgery was used. Routine surgical care was examined with testing of surgeon fatigue and postural measures before and after the procedure. Motor fatigue was measured using a quantitative grip dynamometer, and postural stability was measured using a nondominant, single-leg stance. A subjective fatigue score was recorded following surgery.

RESULTS

Primary surgeons completed testing before and after 56 surgeries. A trend toward decline in postural stability was observed more in the laparoscopy group than in the robotic group (P=.29). The fatigue index and subjective fatigue scores were not significantly different.

CONCLUSIONS

Similar changes in postural stability and muscular strength were observed following laparoscopic and robotic surgery. The optimal measurement tool to capture surgical fatigue remains elusive. Fatigue differences may have been more pronounced if surgical procedure degree of difficulty had been more consistent between groups.

Oculo-vestibular recoupling using galvanic vestibular stimulation to mitigate simulator sickness

INTRODUCTION

Despite improvement in the computational capabilities of visual displays in flight simulators, intersensory visual-vestibular conflict remains the leading cause of simulator sickness (SS). By using galvanic vestibular stimulation (GVS), the vestibular system can be synchronized with a moving visual field in order to lessen the mismatch of sensory inputs thought to result in SS.

METHODS

A multisite electrode array was used to deliver combinations of GVS in 21 normal subjects. Optimal electrode combinations were identified and used to establish GVS dose-response predictions for the perception of roll, pitch, and yaw. Based on these data, an algorithm was then implemented in flight simulator hardware in order to synchronize visual and GVS-induced vestibular sensations (oculo-vestibular-recoupled or OVR simulation). Subjects were then randomly exposed to flight simulation either with or without OVR simulation. A self-report SS checklist was administered to all subjects after each session. An overall SS score was calculated for each category of symptoms for both groups.

RESULTS

The analysis of GVS stimulation data yielded six unique combinations of electrode positions inducing motion perceptions in the three rotational axes. This provided the algorithm used for OVR simulation. The overall SS scores for gastrointestinal, central, and peripheral categories were 17%, 22.4%, and 20% for the Control group and 6.3%, 20%, and 8% for the OVR group, respectively.

CONCLUSIONS

When virtual head signals produced by GVS are synchronized to the speed and direction of a moving visual field, manifestations of induced SS in a cockpit flight simulator are significantly reduced.

The effect of galvanic vestibular stimulation on distortion product otoacoustic emissions

Galvanic stimulation has long been used as a nonmechanical means of activating the vestibular apparatus through direct action on the vestibular nerve endings. This stimulation has been reported to be safe, but no studies have examined the potential changes in the corresponding cochlear receptors. The aim of the present study was to evaluate the effect of galvanic vestibular stimulation (GVS) on distortion product otoacoustic emissions (DPOAEs). Fourteen subjects underwent DPOAEs during several conditions of GVS. The DPOAEs ranged from ∼ 1 kHz to ∼ 8 kHz at 65/55 dB for f1/f2 and with an f2/f1 ratio of 1.2. The subjects were evaluated at 10 stimulation conditions that ranged from −2.0 mA to +2.0 mA for each frequency. Statistical analysis showed no significant differences in DPOAE amplitudes for all conditions with and without GVS. Results also showed no significant differences between DPOAE amplitudes before and after GVS. Multivariate analysis found subject variability in DPOAE amplitude, which was not thought to be GVS related. Results indicated that GVS produced neither temporary nor permanent changes in DPOAEs.

Muscle restricted vasculitis causing dropped head syndrome: a case report and review of the literature

A 52-year-old man presented with a severe head drop and proximal extremity weakness. Magnetic resonance imaging of the cervical spine showed T2 hyperintensity in cervical paraspinal muscles. Electrodiagnostic studies revealed an axial myopathy isolated to paraspinal muscles. A splenius capitis muscle biopsy confirmed an acute myopathy associated with nonsystemic vasculitis. The patient improved on steroids, intravenous immunoglobulin, and monthly pulse doses of cyclophosphamide. Our case emphasizes that a subgroup of patients with dropped head syndrome have treatable conditions.

Synthesis and toxicity of some metabolites of the microbial degradation of synthetic naphthenic acids

Some ill-defined carboxylic acids, termed 'naphthenic acids' (NA), are best known as important constituents of the >720billionlitres of process-affected water associated with the expanding oil sands industries. Other NA are components of some immature and biodegraded crude oils and these may enter the environment via produced water discharges from oil production platforms. Yet others are used as biocides and in the manufacture of steel radial tyres and these may also enter the environment through disposal and/or weathering. The environmental fate of NA, including the mechanisms of biodegradation, therefore needs to be better understood. In order to better elucidate such mechanisms, previously we studied the biodegradation in the laboratory of some alkylcyclohexylbutanoic synthetic NA. However, we could only tentatively identify the metabolites produced. In the present study we report the synthesis and characterisation of six alkylcyclohexylethanoic NA. Each was characterised by gas chromatography-mass spectrometry (GC-MS; trimethylsilyl esters) and we show by co-chromatography that these were indeed the metabolites. Also, a preferential degradation of the trans- isomers was revealed. Assessment of the toxicity of the synthetic NA (Microtox assay), revealed that the relative toxicity of the alkylcyclohexylbutanoic acids was reduced by biotransformation to the alkylcyclohexylethanoic acids, as observed recently for the corresponding aromatic acids. Very recent studies have shown that at least one commercial NA mixture contains cyclohexylbutanoic and alkylcyclohexylethanoic acids, suggesting that the biotransformation of the acids studied herein may be quite relevant to the environmental fate of such acids. A similar study of the acid extractables of one oil sands process-affected water sample suggests that the synthetic acids may be less good 'models' for oil sands NA. The consortia of microbes present in oil sands process-affected water may also be different to those used herein. However, the heterogeneity of oil sands process water is well-known and further detailed studies will need to be made in order to establish whether degradation of oil sands NA proceeds by beta oxidation as observed for the acids herein, or whether the oil sands acids are more resistant to bioremediation.

Demonstration of ignition radiation temperatures in indirect-drive inertial confinement fusion hohlraums

We demonstrate the hohlraum radiation temperature and symmetry required for ignition-scale inertial confinement fusion capsule implosions. Cryogenic gas-filled hohlraums with 2.2 mm-diameter capsules are heated with unprecedented laser energies of 1.2 MJ delivered by 192 ultraviolet laser beams on the National Ignition Facility. Laser backscatter measurements show that these hohlraums absorb 87% to 91% of the incident laser power resulting in peak radiation temperatures of T(RAD)=300 eV and a symmetric implosion to a 100 μm diameter hot core.

You are what you eat, whenever or wherever you eat it: an integrative analysis of fish food habits in Canadian and U.S.A. waters

The degree to which fish diet differs by season and area, particularly over broad scales, was examined for the first time in temperate, contiguous north-west Atlantic Ocean waters by comparing food habit data for 10 species of fishes collected concurrently during the spring and autumn surveys in the U.S.A. (Gulf of Maine proper and Georges Bank) and in the summer survey in Canada (western Scotian Shelf and Bay of Fundy). For most species, there was a general concurrence among the three seasons and four areas: summer diets had the same dominant prey items as spring and autumn diets. Although a suite of multivariate analyses did elucidate some differences in specific proportions of the diet for these species across seasons and areas, the main prey did not substantially change for most of these species. These results suggest that there are (1) minimal differences in diet across season for these species at these taxonomic resolutions, (2) there are minimal differences in diet geographically for these species and (3) differences across species, as expected, are important. Many fisheries ecosystem and multispecies models are dependent on food habit data, where resolving seasonal and spatial differences in diet remains an important consideration; however, the present work implies that amalgamated estimates of diet from seasonal surveys may be a reasonable approach when no finer seasonal resolution exists, as long as due diligence is exercised.

Impact of a computerized physician order-entry system

BACKGROUND

The Institute of Medicine has urged the adoption of electronic prescribing systems in all health-care organizations by 2010. Accordingly, computerized physician order entry (CPOE) warrants detailed evaluation. Mixed results have been reported about the benefit of this system. No review of its application in surgical patients has been reported to date. We present the implementation of CPOE in the management of surgical patients within an academic multispecialty practice.

STUDY DESIGN

Retrospective and prospective analyses of patient-safety measures were done pre- and post-CPOE institution, respectively. Other metrics evaluated included medication errors, order-implementation times, efficiencies, personnel requirements, and physician time. Sampling of time span for the order placement process was assessed with direct hidden observation of the provider.

RESULTS

A total of 15 (0.22%) medication errors were discovered in 6,815 surgical procedures performed during the 6 months before CPOE use. After implementation, 10 medication errors were found (5,963 surgical procedures [0.16%]) in the initial 6 months and 13 (0.21%) in the second 6 months (6,106 surgical procedures) (p = NS). Mean total time from placement of order to nurse receipt before implementation was 41.2 minutes per order (2.05 minutes finding chart, 0.72 minutes writing order, 38.4 minutes for unit secretary transcription) compared with 27 seconds per order using CPOE (p < 0.01). Four additional informational technology specialists were temporarily required for assistance in implementing CPOE. After CPOE adoption, 11 of 56 (19.6%) ancillary personnel positions were eliminated related to order-entry efficiencies.

CONCLUSIONS

Present CPOE technology can allow major efficiency gains, but refinements will be required for improvements in patient safety.

Clinical and electrodiagnostic findings in copper deficiency myeloneuropathy

INTRODUCTION

Copper deficiency is an increasingly recognised cause of neurological impairment. This retrospective review highlights clinical and electrodiagnostic findings in patients diagnosed at our institution with copper deficiency.

METHODS

Clinical, radiographic and electrodiagnostic findings were reviewed in patients with evidence of copper deficiency. Patients with other potential causes of myelopathy or neuropathy were excluded.

RESULTS

The predominant clinical feature in all six patients was a sensory ataxia, resulting in marked gait unsteadiness. Nerve conduction studies and needle EMG were performed in all patients and revealed a mild to moderate distal, axonal, sensorimotor peripheral neuropathy. Median and tibial somatosensory evoked potentials were abnormal in all five patients in which it was performed, showing impaired conduction in central or proximal peripheral somatosensory pathways.

CONCLUSIONS

This pattern of electrodiagnostic findings suggests that impairment in somatosensory pathways demonstrated by somatosensory evoked potential testing is the main cause of the sensory ataxia in patients with copper deficiency.

Cranial Reflexes and Related Techniques

Although a certain level of expertise is necessary, electrophysiologic study of cranial reflexes is not technically demanding, time-consuming, or associated with substantial patient discomfort. The information obtained may document objective abnormality and assist with localization. The blink reflexes are useful for studying the function of the trigeminal and facial nerves and their central connections in the brain stem. When NCS in the limbs suggest a demyelinating peripheral neuropathy, the blink reflex can provide information about involvement of proximal nerve segments. Patterns of involvement of the facial and trigeminal nerves are often helpful in suggesting the type of neuropathy under investigation. The jaw jerk is useful in assessing the mandibular division of the trigeminal nerve, and it can aid in evaluating patients with suspected sensory ganglionopathies. The MIR is sometimes helpful in evaluating patients with demyelinating neuropathies and in assessing central inhibition. The great auricular sensory NCS is a useful method to assess proximal somatic sensory function in the upper cervical dermatomes. The CHEPS technology provides a method to study somatic small fiber sensory pathways from the trigeminal dermatomes to the sensory cortex. Although not discussed in this chapter, needle electrode examination of muscles innervated by the trigeminal and facial cranial nerves are usually performed in combination with cranial nerve reflex studies.

Quantitative Electromyography

The quantitative evaluation of individual MUPs, decomposition of the interference pattern, IPA of turns and amplitude, and frequency and power-spectrum analyses of the interference pattern are all useful techniques. They evaluate different features of the voluntary activity of skeletal muscle, with results probably reflecting different properties of the function and dysfunction of motor units. One method is not necessarily superior to the others. It is likely that the more methods used, the closer the examiner will come to understanding the functional structure of the muscle being studied and whether or not a neuromuscular disorder is present.

A derivatisation and liquid chromatography/electrospray ionisation multistage mass spectrometry method for the characterisation of naphthenic acids

Naphthenic acids (NAs) are partially uncharacterised complex mixtures of carboxylic acids, resulting from the microbial oxidation of petroleum hydrocarbons. They are associated with the fouling of pipelines and process equipment in oil production and with corrosion in oil refineries. As by-products of the rapidly expanding oil (tar) sands industries, NAs are also pollutants and have proved to be toxic to a range of organisms. They also have important beneficial uses as fungicides, tyre additives and, paradoxically, also in the manufacture of corrosion inhibitors. These features make the characterisation of NAs an important goal for analytical chemists. Here we describe the synthesis of amide derivatives of NAs for characterisation by liquid chromatography/electrospray ionisation multistage mass spectrometry (LC/ESI-MS(n)). The method was applied to commercially available carboxylic acids, novel synthetic NAs, commercial NAs refined from crude oils, crude oil NAs and Athabasca oil sands NAs. In addition to confirming the number of alicyclic rings and length of alkyl side chain substituents (confirming information from existing methods), the MS(n) results provided further structural information. Most important of these was the finding that bi- to polycyclic acids containing ethanoate side chains, in addition to alkyl substituents, were widespread amongst the oil and oil sands NAs. The latter NAs are known end members of the beta-oxidation of NAs with even carbon number alkanoate chains. Since such NA mixtures are toxic, they should be targets for bioremediation. Bioremediation of NAs can also be monitored better by application of the methods described herein.

Observation of the suppression of the flux of cosmic rays above 4 x 10 (19) eV

The energy spectrum of cosmic rays above 2.5 x 10;{18} eV, derived from 20,000 events recorded at the Pierre Auger Observatory, is described. The spectral index gamma of the particle flux, J proportional, variantE;{-gamma}, at energies between 4 x 10;{18} eV and 4 x 10;{19} eV is 2.69+/-0.02(stat)+/-0.06(syst), steepening to 4.2+/-0.4(stat)+/-0.06(syst) at higher energies. The hypothesis of a single power law is rejected with a significance greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuz'min.

Upper limit on the diffuse flux of ultrahigh energy tau neutrinos from the Pierre Auger Observatory

The surface detector array of the Pierre Auger Observatory is sensitive to Earth-skimming tau neutrinos that interact in Earth's crust. Tau leptons from nu(tau) charged-current interactions can emerge and decay in the atmosphere to produce a nearly horizontal shower with a significant electromagnetic component. The data collected between 1 January 2004 and 31 August 2007 are used to place an upper limit on the diffuse flux of nu(tau) at EeV energies. Assuming an E(nu)(-2) differential energy spectrum the limit set at 90% C.L. is E(nu)(2)dN(nu)(tau)/dE(nu)<1.3 x 10(-7) GeV cm(-2) s(-1) sr(-1) in the energy range 2 x 10(17) eV< E(nu)< 2 x 10(19) eV.

Copper deficiency myeloneuropathy resembling B12 deficiency: partial resolution of MR imaging findings with copper supplementation

Copper deficiency has been associated with a clinical syndrome, myeloneuropathy. Radiographic changes resembling B(12) deficiency in the cervical spinal cord have been described. We present a case of copper deficiency myeloneuropathy, with cervical MR imaging findings resembling B(12) deficiency, which partially reversed following copper supplementation. This is, to our knowledge, the first described case of radiographic improvement with copper supplementation.

Value of the oral glucose tolerance test in the evaluation of chronic idiopathic axonal polyneuropathy

BACKGROUND

An underlying cause is found in only 7% to 30% of patients with chronic idiopathic axonal polyneuropathy (CIAP). Diabetes mellitus, inherited disorders, toxin exposure, and primary amyloidosis are the most common identified causes of sensory neuropathies affecting both large and small myelinated fibers. Undiagnosed impaired fasting glucose metabolism has been associated with CIAP at a higher frequency rate than in the general population. This increased prevalence rate was identified using the 2-hour oral glucose tolerance test (2h-OGTT) and a previous version of the American Diabetes Association (ADA) guidelines.

OBJECTIVES

To determine the prevalence of abnormal fasting glucose metabolism in patients with CIAP and to compare the value of determining fasting plasma glucose levels using revised (2003) ADA criteria with the 2h-OGTT for predicting abnormal fasting glucose metabolism.

PATIENTS

In this 24-month retrospective study, 100 consecutive patients were identified with no known cause for CIAP, including diabetes mellitus, between January 2003 and January 2005. All had both a fasting plasma glucose test and a 2h-OGTT in addition to a complete neurological examination. Neurophysiological studies, computer-assisted sensory examination, and quantitative sudomotor axonal reflex testing were used to classify CIAP into subtypes according to nerve fiber involvement.

RESULTS

The prevalence of undiagnosed abnormal fasting glucose metabolism was found to be nearly 2-fold higher (62%) in patients with CIAP than in similar age-matched general population groups (33%). Using the 2003 revised ADA criteria, 39 patients (39%) had abnormal fasting plasma glucose metabolism (36 with impaired fasting glucose, 3 with diabetes mellitus), while the 2h-OGTT provided an even higher diagnostic rate of 62% (62 patients; P<.001) of impaired fasting glucose metabolism (38 with impaired glucose tolerance, 24 with diabetes mellitus). The abnormal glucose metabolism rates were found to be similar across the 3 subtypes (sensorimotor, pure sensory, and small-fiber neuropathy) of CIAP (P = .60, .72, and .61).

CONCLUSIONS

This study adds to emerging evidence that abnormal glucose metabolism may be a risk factor for CIAP. Even with revised (2003) ADA criteria, the 2h-OGTT provides additional diagnostic information to the health care professional in the evaluation of CIAP. Subtypes of CIAP are equally likely to have abnormal glucose metabolism.

The influence of xenon, nitrous oxide and nitrogen on gas bubble expansion during cardiopulmonary bypass

BACKGROUND AND OBJECTIVE

Xenon may have favourable applications in the setting of cardiac surgery. Its advantages include a desirable haemodynamic profile as well as potential cardiac and neuroprotective properties. However, its low solubility may lead to enhanced diffusion into enclosed gas spaces. The purpose of this study was to compare the effects of xenon (Xe), nitrous oxide (N2O) and nitrogen (N2) on gas bubble size during cardiopulmonary bypass (CPB).

METHODS

Rats were randomized to receive 70% Xe, 26% oxygen (O2), 4% carbon dioxide (CO2) (xenon group); 70% N2O, 26% O2, 4% CO2 (nitrous oxide group) or 70% N2, 26% O2, 4% CO2 (nitrogen group) during 90 min of normothermic CPB. Small gas bubbles (300-500 microL; n = 12 per group) were injected into a bubble chamber on the venous side of the bypass circuit. After 10 min of equilibration, they were removed for volumetric analysis.

RESULTS

The increase in bubble size was 2 +/- 2% with nitrogen, 17 +/- 6% with xenon (P = 0.0192 vs. nitrogen) and 63 +/- 23% with nitrous oxide (P = 0.0001 vs. nitrogen). The nitrous oxide group had significantly increased bubble size compared to the xenon group (P = 0.0001).

CONCLUSIONS

During CPB, xenon anaesthesia produced a small increase in gas bubble size compared to nitrogen. Nitrous oxide resulted in significantly larger bubbles compared to both nitrogen and xenon.

Structures of a blue-copper nitrite reductase and its substrate-bound complex

Copper-containing nitrite reductases (NiR's) have been conveniently subdivided into blue and green NiR's which are thought to be redox partners of azurins and pseudo-azurins, respectively. Crystal structures of two green NiR's have recently been determined. Alcaligenes xylosoxidans has been shown to have a blue-copper nitrite reductase (AxNiR) and two azurins with 67% homology both of which donate electrons to it effectively. The first crystal structure of a blue NiR (AxNiR) in its oxidized and nitrite-bound forms, with particular emphasis to the Cu sites, is presented. The Cu-Smet distance is the same as those in the green NiR's. Thus, the length of this interaction is unlikely to be responsible for differences in colour. Crystallographic data presented here taken together with structural data of other single Cu type-1 proteins and their mutants suggest that the displacement of Cu from the strong ligand plane is perhaps the cause for the differences in colour observed for otherwise 'classical' blue Cu centre. Nitrite is observed binding to the catalytic Cu in a bidentate fashion displacing the water molecule, offering a neat rationalization for the XAFS observation that the type-2 Cu-ligand distances increase on nitrite binding as a result of increased coordination. These results are discussed in terms of enzyme mechanism.

Delayed ulnar neuropathy at the wrist following open carpal tunnel release

Open carpal tunnel release is a common and successful treatment of median neuropathy at the wrist (carpal tunnel syndrome). We report a case of delayed ulnar neuropathy at the wrist with onset 2 months after open carpal tunnel release. Clinical findings, electrophysiological studies, magnetic resonance imaging, and surgical exploration demonstrated ulnar nerve compression at Guyon's canal resulting from translocation of the carpal tunnel contents. To our knowledge, this is an unreported complication of open carpal tunnel release that merits wide appreciation.

Pain and anxiety reduction using a manual stimulation distraction device when administering local analgesia oro-dental injections: a multi-center clinical investigation

OBJECTIVE

This study was designed to assess the effects of a manual stimulating distraction device (Isoflex referred to as Manual Stimulation Distraction Device or MSDD) for reducing pain and anxiety experienced with standard dental local anesthetic injections. Additionally, the memory recall effects on injection pain and anxiety were also explored.

METHODOLOGY

Patients from different dental clinics were identified by their practitioners as requiring dental procedures under local anesthesia, in the same area on both sides of the mouth. A local anesthetic solution was injected on either the left or right side at different times by random selection; one side using MSDD, while the opposite side used a solution without MSDD. Each patient acted as his or her own symmetrical split-mouth control. The same dentist administered both injections, using identical technique and equipment for each side. Forty-six patients used the MSDD first with the injection, while 54 used MSDD second when they received the injection. Using 10-point visual analogue nominal and ordinal scales, pain and stress were recorded by the patient each time after receiving the injection. The results were pooled and subjected to statistical analysis. Student's paired t-test was employed to test for significant differences in pain and anxiety (stress) when injections were administered with and without MSDD.

RESULTS

Results showed significant reductions in perceived pain and stress from local analgesia injections (p < 0.001) when MSDD was used. There was no correlation of pain reduction with age, gender, upper or lower jaw, with or without MSDD. There was a trend for pain and stress to be scored higher for those subjects who had a lower period since the first injection (POFI) scores. This was attributed to recent memory of pain, as POFI scores over one week were significantly lower (p < 0.05). Stress reduction for POFI scores greater than one week proved to be non-significant (p = 0.099).

CONCLUSION

In this study, MSDD was effective at reducing pain and stress experienced with local regional analgesic injections.

What good is EMG to the patient and practitioner?

Electromyography (EMG) and nerve conduction studies (NCS) are not only tests to be performed in isolation and reported without consideration of the clinical context, but rather form part of what has been referred to as the electrodiagnostic consultation. Using all of the pertinent information available to the electromyographer performing the test, the electrodiagnostic consultation strives toward the goal of helping the patient and the referring physician to establish a correct diagnosis. Although not without limitations, EMG as an extension of the clinical history and physical examination can be a powerful and sensitive diagnostic tool. Like any tool, however, the final result depends on the skill and expertise with which it is wielded.

Motor unit number estimates in idiopathic Parkinson's disease

We previously reported changes in motor unit morphology in patients with Parkinson's disease (PD) using subjective and computerized quantitative electromyography. Now, we present data on motor unit number estimates (MUNE) to address the hypothesis of motor neuron dropout in PD. Twenty patients with PD and 20 age-matched control subjects were screened by clinical criteria and nerve conduction studies to exclude those with neuropathy. Motor unit number estimates in the extensor digitorum brevis and hypothenar group were assessed by three different MUNE techniques. The MUNE technique types included (1) the statistical method developed by Daube, (2) a threshold method, and (3) an F-wave method. The overall multivariate comparison for the six MUNE measurements was significantly lower for the patients than the controls (P=0.02). The only significant difference in the individual measures was found in the threshold MUNE method of the hypothenar group (P<0.05). These results are consistent with those of our previous work, and both support the hypothesis that mild motor neuron dropout occurs in idiopathic PD. However, MUNE methods characteristically have large standard deviations which make it difficult to detect small changes. Progress in decreasing the variance of MUNEs will facilitate their use in detecting small motor unit number changes in neurodegenerative disease.

Kroeyerina deetsorum n. sp. (Copepoda: Kroyeriidae) from the olfactory sacs of Atlantic sharpnose sharks (Rhizoprionodon terraenovae) captured in the Gulf of Mexico and northwestern Atlantic and first report of copepodids representing Kroyeriidae

Kroeyerina deetsorum n. sp. (Copepoda: Kroyeriidae) is described from female and male specimens collected from the olfactory sacs of Atlantic sharpnose sharks, Rhizoprionodon terraenovae (Richardson, 1836), captured in the Gulf of Mexico and northwestern Atlantic. Kroeyerina deetsorum is easily distinguished from known congeners by the extremely small size of its adults (i.e., females about 1.2 mm total length and males about 1.0 mm total length). Kroeyerina deetsorum is also distinguished from its congeners by possessing a subquadrate rostrum without lobes or upturned horns. It is suspected that K. deetsorum belongs to a clade within Kroeyerina whose members only infect sharks. This report also provides first descriptions of a nauplius representing Kroeyerina and copepodids representing Kroyeriidae. The early-stage copepodid of K. deetsorum lacks a frontal organ and frontal filament and uses its chelate antennae to attach to its host.

The frequency of carpal tunnel syndrome in computer users at a medical facility

A survey was done of employees who were identified as frequent computer users. Although 29.6% of the employees reported hand paresthesias, only 27 employees (10.5%) met clinical criteria for carpal tunnel syndrome, and in 9 (3.5%) the syndrome was confirmed by nerve conduction studies. Affected and unaffected employees had similar occupations, years using a computer, and time using the computer during the day. The frequency of carpal tunnel syndrome in computer users is similar to that in the general population.

Changes in speech following maxillary distraction osteogenesis

OBJECTIVE

The purpose of this study was to describe changes in articulation and velopharyngeal function following maxillary distraction osteogenesis.

DESIGN

This is a descriptive, post hoc clinical report comparing the performance of patients before and after maxillary distraction. The independent variable was maxillary distraction while the dependent variables were resonance, articulation errors, and velopharyngeal function.

SETTING

The data were collected at a tertiary health care center in Chicago.

PATIENTS

The data from pre- and postoperative evaluations of 18 maxillary distraction patients were used.

OUTCOME MEASURES

The outcome measures were severity of hypernasality and hyponasality, velopharyngeal orifice size as estimated using the pressure-flow technique, and number and type of articulation errors.

RESULTS

At the long-term follow-up, 16.7% exhibited a significant increase in hypernasality. Seventy-five percent of patients with preoperative hyponasality experienced improved nasal resonance. Articulation improved in 67% of patients by the 1-year follow-up.

CONCLUSIONS

In a predominately cleft palate population, the risk for velopharyngeal insufficiency following maxillary distraction is similar to the risk observed in Le Fort I maxillary advancement. Patients being considered for maxillary distraction surgery should receive pre- and postoperative speech evaluations and be counseled about risks for changes in their speech.

Changes in speech following unilateral mandibular distraction osteogenesis in patients with hemifacial microsomia

OBJECTIVE

The purpose of this study was to describe changes in articulation, resonance, and velopharyngeal function following mandibular distraction osteogenesis.

DESIGN

This is a descriptive, post hoc study comparing the performance of patients on measures of articulation, resonance, and velopharyngeal function before and after mandibular distraction.

SETTING

The data were collected at a tertiary health care center located in Chicago.

PATIENTS

The clinical data from preoperative and postoperative evaluations of seven mandibular distraction patients were used.

OUTCOME MEASURES

The outcome measures were number of articulation errors, severity of hypernasality and audible nasal emission, and velopharyngeal orifice size as estimated using the pressure-flow technique.

RESULTS

Immediately after distraction, 28% (2/7) experienced a temporary deterioration in articulation and 42% (3/7) experienced a deterioration in nasal resonance. But by the long-term follow-up evaluation, all had returned to their preoperative levels. Pressure-flow test results generally support the perceptual findings.

CONCLUSIONS

Patients being considered for mandibular distraction surgery should receive preoperative and postoperative speech evaluations and be counseled about risks for changes in their speech following surgery.

Transition state complexes of the Klebsiella pneumoniae nitrogenase proteins. Spectroscopic properties of aluminium fluoride-stabilized and beryllium fluoride-stabilized MgADP complexes reveal conformational differences of the Fe protein

Stable inactive 2 : 1 complexes of the Klebsiella pneumoniae nitrogenase components (Kp2/Kp1) were prepared with ADP or the fluorescent ADP analogue, 2'(3')-O-[N-methylanthraniloyl] ADP and AlF(4)(-) or BeF(3)(-) ions. By analogy with published crystallographic data [Schindelin et al. (1997) Nature 387, 370-376)], we suggest that the metal fluoride ions replaced phosphate at the two ATP-binding sites of the iron protein, Kp2. The beryllium (BeF(x)) and aluminium (AlF(4)(-)) containing complexes are proposed to correspond to the ATP-bound state and the hydrolytic transition states, respectively, by analogy with the equivalent complexes of myosin [Fisher et al. (1995) Biochemistry 34, 8960-8972]. (31)P NMR spectroscopy showed that during the initial stages of complex formation, MgADP bound to the complexed Kp2 in a manner similar to that reported for isolated Kp2. This process was followed by a second step that caused broadening of the (31)P NMR signals and, in the case of the AlF4- complex, slow hydrolysis of some of the excess ADP to AMP and inorganic phosphate. The purified BeFx complex contained 3.8 +/- 0.1 MgADP per mol Kp1. With the AlF(4)(-) complex, MgAMP and adenosine (from MgAMP hydrolysis) replaced part of the bound MgADP although four AlF(4)(-) ions were retained, demonstrating that full occupancy by MgADP is not required for the stability of the complex. The fluorescence emission maximum of 2'(3')-O-[N-methylanthraniloyl] ADP was blue-shifted by 6-8 nm in both metal fluoride complexes and polarization was 6-9 times that of the free analogue. The fluorescence yield of bound 2'(3')-O-[N-methylanthraniloyl] ADP was enhanced by 40% in the AlF(4)(-) complex relative to the solvent but no increase in fluorescence was observed in the BeFx complex. Resonance energy transfer from conserved tyrosine residues located in proximity to the Kp2 nucleotide-binding pocket was marked in the AlF(4)(-) complex but minimal in the BeFx fluoride complex, illustrating a clear conformational difference in the Fe protein of the two complexes. Our data indicate that complex formation during the nitrogenase catalytic cycle is a multistep process involving at least four conformational states of Kp2: similar to the free Fe protein; as initially complexed with detectable (31)P NMR; as detected in mature complexes with no detectable (31)P NMR; in the AlF(4)(-) complex in which an altered tyrosine interaction permits resonance energy transfer with 2'(3')-O-[N-methylanthraniloyl] ADP.